Fuel injection nozzle



y 1945- w. TQTABB ET AL 2,376,292

FUEL INJECTION NOZ ZLE Filed Sept. 26, 1941 s Sheets-Sheet 1 I INVENTORS Warner T Talzb Evereii M. I rdq May 15, 1945. w; T. TABB ET AL 2,376,292

FUEL INJECTION NOZZLE Filed Sept. 26, 1941 s sheets sheet 2 51 I 1% 3g 4g 40 4g y Q 6 1.58 L/ 6 1&4 f y INVENTOR Y BY dz Patented May 15, 1945 UNIT so. STATES, PATENT o j A amaze/2 v t t noon INJECTION nozzmz Warner flabib rand", lilverett Burdy; BrojoklynQ N. 1.; assignors, by mesne assignments, to Reconstruction Finance Corporation, New York, Nags corporationof the United States Application September as, 1941, Serial s cia se Aeeneral object of the invention isiithe provi sion of an improved nozzle {construction and ar-V rangement of pants thercofsuitably adapted :for

efficient injection of fuel into 'combustionchamhers, characterized by simplicity of construction making :for ready and izeconomical commercial p 7 omms. (01. 210- 166) This inventionirelates to a nozzle riorfuel umfiedin the construction hereinafter setlforth a-nd the scope of the invention will be indicated in the claims. 1

:a fuller understanding of the mature and objects of the invention reference should behad to the iollowingdetailed description taken in=connection with the accomp n n a in which: l l

production, a positive valve stem guidance at ce-rart-n remote moints thereby simplifying essent-ial alignment by valve :stem bearings and concentricity of parts, {hitching of'fuel, ready interhanseability and removal of parts for adaption to different desired servic s in the structure and ready" cleaning making tor minimum number of parts:Withmaximumtefiectiveness. or A more specific object oi the invention is \th, provision in such a nozzle structure of -a filter bushing structure adapted .efiectively to serve asa valve stem guide and to provide abutment means for limitin travel thereoi.

Another object of the inventionhi s the pnovis-ion of such anozzle construction wherein a readilyv removable tip member is pnovided with a socket as an enlargement of a fuel passing borein which such filter bushing structureis mounted IfOI' easy and ready removal ioreleanings t v o A'iurther object of the invention is the provi- SiOIJ-rin the tip member of sucha nozzle construction of such a filter bushing stnucture which includes :a portionprojecting :from the upstream end otthe tip member to serveuefiectively as a uide for valvestemsprins biasin means.

still another object is to provide such a con nigh 'isfa, mo partly-tin section and also elevation with parts broken away, showing a fuel injection nozzlelof the present invention adapted for support \bya suitable holder n a wall which maybe that of an internal-combustion engine;

Fig. 2 is a perspectiveview of a travel limiting means or washer adapted ;for use in the structure showninl ig. 1-1; I t

Fig. 3 is-a perspective view of a part -of filter.

bushing structure shown in Fig. 1;

mo e is a s View similar to Fig. 1, with similar parts omitted for clarity, of a modified form of the (apparatus of the present invention;

Fig. 5 is a jViBW similanto 2 ;of a; similar element; 1 t Fig. -6 is a perspective-view of filter bushing structure shown in'Eigml; i t

- Figs. Wand 8 are vertical sectional views with par-ts broken away and omitted tor clarity, of

. modifications of the structure shown in Fig; 1;

A viewsoffurther :modi-fied structure described herei struotion wherein abutment means on filterbushing structure in a tip member cooperates with valve stem spring biasing means to limit travel of the filter bushing structure therebywavoiding necessity of additional securing m ans. 1 1

A still further object of the invention is the provision in such a nozzle construction of asubassembly complete in and of itself with the parts thereof inclusive of a tipmcmher, filter unit-valve andvalve stem travel limiting stops and spring i ging, arranged in seoune lfa-shionin relative adjusted position for certain service which can after assembly andadjustment of parts be easily and simply mounted as a unit to a nozzle body unit to complete a nozzle construction ready for efilcient service.

Other objects of the invention will" in part be obvious and will in part appear hereinafter.

The invention accqrdinigly comprises the features of consttuction, combination of t elements,

and arrangement of parts, which will be exempli- Figs. Sand '10 are sectional fragmentary views of tunther modifications-of the structure shown in Eig lgand l i t 1 w ig. ill ,is atf-ragmentary elevational sectional Referring now to the drawings and particularly to Figs. 1 and 4, all] denotes atip member which has a flange H about its upper end by which it is held in a retainer 'nut 12 of a holder member l3 cooperating with the tip member 1|] to complete ther nozzle construction. This latter is arranged to pass through and be secured in an opening in a wall (not shown) of a combustion chamber by suitable means, such as a suitable plate (not shown) which has an opening for engaging with the-top surface of a flange .14 on the member 13;

the clamp being provided with openingsfor the reception of screws, orth'e like,:1or securing the clamp to the wall of the internal combustion chamber. The retainer nut 12 and the nozzle member I3 are here shown in threaded engagement but any convenient means for securing the same in assembled relation may be employed. Thetmember I3 is here provided with a central bore; 15 by which fuel is supplied from a suitable source (not shown) and pumped under a desired pressure. [Bore I5 leads into an enlargement or working chambernl 5 in which is housed the upper portion oftnozzle mechanism, as hereinafter ex -y tion 22 that is provided at the junction of the stem proper'with its enlargement l9. This latter, it will be understood, may be given any de-' sired form, i, e., it may be grooved, slotted, etc., whereby desired shape is imparted to the jet of fuel which is ejected from the nozzle. The enpassages such as a plurality of notches 38-38 larged portion preferably is provided with surfaces coacting with the inner wall of the bore 20,

which may be cylindrical as shown, for reciprocative guidance of the stem, such as those shown at 23-23 which preferably conform to circular arcs. Downstream of the guiding surfaces 2323 the stem enlargement l9 may be, if desired, substantially frusto-conical as shown so that the surface thereof gradually approaches to engage ment with the surface of the bore 20, whereby a discharge orifice will be formed between the-frusto-conical valve stem portion andthe bore when the valve stem is moved outwardly with valve trally bored at 35 guideably to receive shank portion 3| to provide a bearing therefor. A shoulder 36 is preferably provided on portion 33 to serve as a seat for a, ring or washer 31 which together may. act in cooperation with spring rigging to limit travel of filter bushing structure 26 as hereinafter explained.

The base 34 is suitably provided with fuel and the cylindrical surface of the portion 33 and shoulder 33 may be set back, such as by fiatting off at 39-39, to provide for free passage of fuel past the washer 3'! and other structure,

e. g., the spring means.

'When' the nozzle tip I0 is thus bored and counterbored and the filter bushing structure 26 and valve stem [8 slipped into place, the conical valve portion 22 seats on the shoulder 2| and closes the passage. The shank portion 33 of the stem projects beyond thetop of the tip member I3 and filter bushing structure 26 and has disposed about it a spring rigging in accordance with the invention in order to control the movement of the stem, the arrangement being such that the opening movement; and the effective cross-sectional area of the so-formed orifice will be gradually increased upon such valve stem movement.

The bore I1 i further counterbored at 24 upstream of the valve seat shoulder 21 to provide an enlarged socket having a bottom wall 25. This socket receives a filter bushing structure 26 or I26 having the downstream end thereof seated against the wall 25. e

As in Figs. 1 to 3 inclusive the filter bushing structure may comprise a, pair of solid metal rings 21 and 28 between which is located a member or sleeve 29 of porous material such as Moraine metal, Porex, porcelain or the like.

opening movement is' substantially proportional to the pressure difference between that of the fuel in the chamber l1 and that of the fluid into which the fuel is being injected, such as that in the cylinder'of the engine.

Accordingly, valve stem spring biasing means such as a helical spring member 49 is provided and disposed about the projecting end of the valve stem shank portion 3| and arranged to seat at M on the upper end of tip member [0. The upper endof spring member 40 reacts against a dual member or nut assembly comprising an outer member 42 andan inner member 43, the latter When [sleeve 29 is formed from Moraine'metal the rings 21 and 28 may be fused or otherwise secured thereto to provide a unitary structure. The sleeve 29 is suitably spaced at 30 from the valve stem I8 for manufacturing and other rea sons, this being permitted by suitable guidance of the valve stem elsewhere. Obviously rings 21 and 28 may be omitted with suitable provision at the opposite ends of the sleeve 29for obtaining the desired or required fluid seals relative to the valve stem l8 and socket 24. This may be provided by the sleeve 29 itself having at one end a substantially fluid-sealing sliding fit with the valve stem and at the'other end a substantially fluid-sealing fit with a wall of socket 24. Thus either rings 21 and 28 or the ends of sleeve 29 itself may form end means providing the fluid seals.

The valve stem I8 is provided with a shank portion 3| which is guideably received in the ring 28 for proper centering of the sleeve 29 in the socket 24, whereby suitable spacing for passage of fuel is provided at 32 between the outer surface of the sleeve 29 and the cylindrical Wall of the socket 24.

Upon the ring 28 is'mounted a substantially cylindrical projecting portion 33 which, if desired, may be made integral with ring 28, but as shown in Figs. 1 and 3 may be separately formed for ring 28 and snugly received in the upstream end of socket 24 for proper centering; andis cenpreferably but not necessarily being inthreaded engagement with the projecting end of the shank of the stem.

-The valve stem shank portion 3|" extending through the projecting portion 33 preferably has a group or stack 44 of superposed washer or shim members,'prefe rably formed from spring steel or phosphor-bronze, slidably disposed on the stem shank; the number of such shim members being less than enough to fill the space between the inner nut 43 and the upstream end of projecting portion a 33. A clearance space thus remains, which determines the limit of downward movement of the stem l8 and its member or nut 43. The shim members may be slightly dished or otherwise shaped or arranged to have a cushioning effect when engaged by the member or nut 43 for stopping the downward stem movement. The shim members 44 and backing collar 21 are thus seen to serve as an efiicient stop which may have mechanical resiliency for determining the amplitude of stem movement, and to require a minimum of space while making for ease in assembling the nozzle parts and simplicity of manufacture.

During fuel injection operation of the device (which in the case of internal combustion engines is characterized by high frequency reciprocation of the valve stem) with the shim members slightly dished, distorted or substantially flat (preferably the latter), films of small bodies of fuel are present therebetween during intervals between impacts by the stop member or nut 43 by virtue of the location of the stack of shim mem bers in the fuel chamber Hi. When stop member or nut 43 violently impacts against the stack of shim members at least portions of the intervening bodies of fuel are squeezed out against opas-aaeez posing forces, "that "may be; due to capillary ac tion and/or adhesion between the intervening films of fuel and the surfaces of the shim members or fluid friction, thereby providing -an*l1ydraulic cushioning effect, with which may oooperate certain mechanical resilienoy due to shape of shim members, eta, tending Jtoavoid hammering of the metal shim members and the stop member ornut, destruction 01' distortion-oi threads on"the nuts and stem, and-damaging shoclrto -the-stemand related parts. it is under stood 'of course that when *the fuel pressure drops and the spring returns the valve stem to its initial' position interveningbodies of fuel are re stored to the stack of shim members such asfibl capillary action. It is thus important tohave a *fair extent of contiguous shim member surfaces whether the shim members be substantially lilat or otherwise shaped so as to assure attainmentof this hydraulic cushioning effect. it 'Such structure 1 tion thereof :a swivel plate lll may be interposed between nut flange ll and the upstream end of tension by not member llhave been thus provided the inner andouter nut members mayfbe locked together' by "any suitable means (not shown) such as pins, and the like seated in matching grooves inthetwo nut members.

For the purposes of 'properly centering the,

helical spring nland providing for balanced ac the spring, withthefflange andplate provided with cooperating tapered surfacesx Proper centeri-ng and guidance of the downstream end of the spring 40: is 'providedby projecting portion v 33 which has the cylindrical surfaces thereof -in- 3VOiS-filGeSSity -of using :a secondary spring 1 which may be subject to ha-mmeri-ng damage, shock and fatigue fail-urew i The stack M of shim members might be loose- 1y carried on the valve stem shank portion '31 by suitable means such as an adjustable collar but j anycase such structure intervening between projectingportion 33 and member M on the stem members 52 and 4:3 andspringf iil', may beassembled as a sub-assembly unit mthcthe parts thereshanlrportion 3| cooperate with the two latter 1 elements to provide-abutment means predetermining" valvestem travel. Any such arrangementrnakes possible ready attainment of any a desired amplitude of valve opening movement, by

altering the number of shim members on the stem shank, a ndyor by the adjustment of inner ,nut 4'3 0n the'stem shank. Nut 43 when properlv adjusted is preferably locked imposition. To thisend, a transverse slotfifi'is formed in the nut 4'3 in orderto accommodate the ends of a looking pin i'fi. For the reception and engagement otf this pin, theupper end of stemshanlo-port ion 3% is perforated transversely. In consequence," it

a is seen that the adjustment of stem movement provided is independent of any other adi'rustment. and may be achieved withprecision at the time of assembly. It is thus obvious that stop member 63 need not be athreaded nut. It. may be collar suitably mounted onthe stem 'suc'h as by a :;in,pins, spring rings, .etc. g "The innerstop member or nut 4-3 is threaded and fit is thefirst member of the assembly 'to be put in place. The lower end of stop member or nut 43 is also advantageously thickensd, as

- shown, in order to impart stiffness thereto when functioning asya stop. When the inner nut mern ber Or nut is threadedupo'nthe valve stem shank and the in 46 inserted for holding itin adjusted position, spring A l! may be slipped into place thereover and {outer member or nut 42 then suitably positioned or threaded upon inner =member or nut 43 to hold the assembly together.

; The outer member or'nut flfi, as zshcwn preferably has interior threadsonly for engagement with theou-ter threads ofinner member nut 6'3, and is provided with a laterally extending flange A which provides a reacting. abutment and, if desired, a seat for the upper end of spring A0. By this arrangement, it -is seen that may member or nut '42 may be turned into a position onirmer member or 'nut 53 so as to compress spring 413 to any desired degree, 1, cause spring 40 to give any desired reacting presrmre. Any

, desired opening pressu refor the valve stem may thus be had. When the desired adjustment of valve stem travel by nut member-4:3 and; spring ,val-ve stem travel .islimited bythe projecting porofyad'justed relative to eachyotheruinfthe desired mannerso that 'towadapt it vto service all that is required islthe mounting thereof tothe nozzlewuni'tqfi by thefinetaiher amt l2. i

In operation, fuel under pressurelis supplied to chamber 1'5 by bore: or passage 1:5: and when the biasing force Of ithLB spring -411- is overcomethe valve stem l8. moves dmvnstreamto open valve 22 and projectstemfportion i9 outwardly of the tip. member ill to provide a .jet opening between the wall ofboreZ-il ancl'surfaces of stem portion l 9.x Fuel will then flow from chamber l6 between adjacent turnswof the downstream end of spring Ml, therepast between spring turns and projecting portionfi via flats. or set backsn3'9-3-H1, ti'zrough washer 33' and passages provided by notches sa-sa to lure space 32 betweenthe cylindrical wallof; sunken-Hand filtersleeve 29. By virtue of the porosity of sleeve .ZQ the fuel pas-sestherethrough, foreign particles being blocked off to space The-filtered. fuel than flows down be.- tweenfilter. structnitewandrvalve stem #8, past the valve at=22., between. the stem portion iflkand wall of bore 216 to-and throughthe jet opening.

It will thus-be seen that the filter structure is placed immediately upstream of the discharge va1vetoobtainmaximum filter protection.

The. downstream travel of the valve stem is accuratc1yguided: by the bearing, provided in projecting portion 33, preferably v cooperating with guidance provided by the counter-bored section '21! ofthe tiplnem-berwiril. Downstream tion 33 and travel limiting nutmember 43 in cooperation with the interposed stack M of shim.

members. V

Uponsuilicientreductionof pressure of fuel in chamber it the spring All returns the nut rigging and valve stem to their initial position thereby c1osing the valve at 22. a If such retraction of the valve stem should tend to movcxthefilter bushing structure :25 upstream :out of the socket 2 'thislravel is limited "by the shoulder 35 and.

downstream end of spring M overhanging the in cooperation with interposed 3T.

. In themodification shown in Figs. 4, :5; and '6;

parts similar to those of the structure-showniin- Figs 1, 2and 3 bear similar numerals. The filter bushing structure here shown comprises a substantially cylindrical sleeve portion 50 seated. in the socket 24 very slightly spaced, such as a few thousandths of an inch from the cylindrical wall thereof by flanges 5| and I34 to form space I32. The downstream end of the bushing portion 55 seats against socket bottom wall 25 and the bottorn arris of flange 5| is chamfered off at 52 to cooperate with a plurality of radial grooves 53-53 to provide for free passage of fuel.

The substantially cylindrical projecting portion I33. provided with shoulder 36, flats or set-backs 39-39 and curved surface portions 48-49, is here shown made integral with sleeve portion 55 with the flange I34 serving asthe base of that portion provided with fuel passing grooves or notches I38-l38.

The notches l38-l38 communicate with and are preferably formed with a series of longitudinally extending grooves 54-54, preferably V-shaped in cross-section, extending downstream for a considerable portion of the length of bush ing section 5|. These grooves 54-54 are alternated with similar longitudinally extending grooves 55-55 extending upstream for a considerable portion of the length of bushing section 5!] from the chamfering at 52 through flange 51.

These alternated grooves 54-54 and 55-55 are blanked off at their respective ends asshown and provide intervening ribs 56-56. The flanges 5i and I34 have a close fit with the cylindrical wall of the socket 24 properly to align the filter bushing structure and the valve stem shank bearing in projecting portion I33 thereof.

In operation of this second modification, when pressure of fuel in chamber l 5 is sumcient to open the valve at 22, fuel flows between downstream turns of spring 40, down between those turns and portion I33 through spaces provided by flats 39-39, through washer I31, through notches l38-l38 and into grooves 54-54. Since the ends of the latter grooves are blanked off as shown the fuel is forced to pass to grooves 55-55 across the intervening ribs 56-56 through the minute space I32 which results in particles of foreign matter of appreciable dimension being blocked out of the passing fuel. The so-filtered fuel then flows down through grooves 55-55 to space provided by chamfering at 52, through notches or grooves 53-53 to the bore 11, past the valve at 22 and out through the jet opening.

other suitable shape such as curvilinear or rectangular in cross-section within the scope of the invention.

The present structure is readily adapted to the provision or omission of a filtering unit in a nozzle construction at will; the filter bushing structure being readily removable from the tip mem her. If it is desired to omit the filtering feature a solid bushing similar to that shown at I26 in Fig. 4 may be provided, in which no alternately arranged longitudinal grooves such as 54-54 and 55-55 are provided. Such abushing is shown stem and the bore of the bushing may be providedby a series of holes therethrough such as at the location indicated at 58, around the-circumference thereof. I

Further the structure shown in Figs. 1, 2 and 3 may be modified by fitting the outer circumferential surface of the upstream end of the filter bushing structure or the end ring 28 thereof to the inner surface of the socket 24 and providing a slide fit between the inner circumferential surface of the downstream end of the filter bushing structure or end ring 21 thereof and the surface of the valve stem [8. Such fits of course should provide substantially fluid-sealing means at longitudinally spaced points with the means comprising either portions of the porous sleeve itself or structure engaged by it or secured thereto such as end rings. This necessitates provision for passage of fuel from chamber it to between the upstream end of filter bushing structure and the valve stem which may be accomplished if desired by passages located in the vicinity of passages indicated in dotted lines at 51 in Fig. 4, such as by notching one or both-of the meeting surfaces of end ring 28 and projectingportion 33. In such case the downstream end of the filter bushing structure will be so formed in relation to the bottom of the socket 24 as to permit of passage of filtered fuel from between the socket wall and filter bushing structure to the bore [1, such as by notching as in Fig. 4, or making the outer diameter of end ring 21 less than the diameter of the socket and supporting the bushing structure 'on spaced apart lands on the socket bottom wall 25, or circumferentially spaced intervening members, and the like.

Fuel will then pass from chamber it through between convolutions of spring 45, through'sug gested passages to between filter bushing structure and valve stem l8. The'fuel will then be filtered as it passes through the porous sleeve 29 from the space inside thereof out to the space between the wall of socket 24 and the porous sleeve, after which it will pass at the bottom of the socket to the bore l1 and through the valve at 2|.

Such a structure as that last described above is shown in Fig. '7 wherein a filter bushing structure 226 includes a sleeve 229 of porous material of the type previously indicated located between a pair of solid metal rings 221 and 228 which, if desired, may be fused or otherwise secured thereto. The ring 228 at the upstream end of the sleeve 229 is preferably fitted into the socket 24 to provide-a relatively tight fluid seal and is suitably spaced from the shank portion til of the valve stem as shown. The ring 221 in thebottom of the socket 24 is'provided with a sliding fit on the valve stem also to obtain a relatively tight fluidseal with the sleeve 229 spaced from the valve stem to provide an inner fluid space 230. The sleeve 229 is also spaced from the side wall of the socket 24 to provide an outer fluid space 232. A plurality of radial grooves 251-251 are preferably provided in the upper face of the ring 228 and similar grooves 253-253 are provided in the lower face of the ring 221 to provide fuel passages.

Accordingly when the valve stem is'r'orced outwardly by fluid pressure to open the valve at 2| the structure shown in Fig. '7 will operate in the following manner. Fuel will pass through the plurality of notches 38-38 in the base of the portion 33 of the filter bushing structure, thence glg ough grooves 251-251 to the inner fluid space Then, by virtue of the fluid-seal between the lower ring 221 and the valve stem, the fuel c evasse in space 2.3a is caused by pressure to be forced thirough. the porous "filtering sleeve 1229.- .to the outer: flui-ctspace 232 with foreign particles and the like inIthefuel being blocked; 01f by the filter sleeve-to the spaceuzdfll Thefilterediuel then pa'mesthroughathe grooves 253-2 53 to thecentral bore Ill; and betweenvthe wallthereof andgthe I valve stem; I81 past theopened. valve at. 2|.

previously mentioned end rings, suchas those atl laan'd 28 of Fig. l may be omitted. Sucha structure is shown by way of example. in Fig. 8

seal. A. plurality of grooves 438- 438 similar to grooves 38.-33-of the. structure shown in Figs.

. I-3-. provide for passage of. fuel; to the-outside of wherein a. filter bushing structureflfitcomprises a sleeve 329.:of porous material and a projecting portion 33. separate. therefrom but positioned on the upstream end thereof within. the socket 24.

The. sleeve 329 of porous material; is preferably provided with enlargements 321' and 328st the I downstream andz'upstreami ends thereof respectively to provide a relatively tight fluid-seal with the-socket wallat the bottom and a relatively tight fluid-seal with the shank of the valve stem at or near the upstream endof socket 24. It will be noted that the fluid-seal in the bottomof the socket may be augmented by proper fittingof. the

sleeve 329 to the bottom wal1 of the socket 24.

The resultant. structure provides. an inner fuel space 330 between the valve stem l8 and at least th mid-section of the sleeve 329 and an outer fuel space 3-32 between the socket wall and at least the mid-sectionof the sleeve 3-29. The flow of fuel after passing through the notches 38 38 in this modification is similar to thatlin the structure shown in Fig. 1.

Obviously various types of enlarged valvestem heads: maybe used for cooperation with counterthe walllof the bore 20with the remaining portion I23 ofthe cylindrical surface providing further guidance. Thus the surfaces of the fiatsor set back portions Bil-4S0 and the wall of the bore 20 gradually converge downstream of the structure to provide an orifice the efiectiveycross-section of; which will be gradually increased. as the valve stem progressively moves outwardly. Further as shownJin Fig. 8 such a transverse groove as 59 may be omitted and the. flats 58-58 may merge directly intothe diverging flats 60-6Ilwith the remaining portion 223: of the surface of the enlarged end of the valv stem. providing with the wall of thebore 20 guidance for the downstream end of the valve stem. v l v 1 previously suggestedthe upstream ring 28 may be made integral with thelportion 33. Such astructure is shown infragmentary. detailin Fig. 9 wherein the filterbushing-structure 426 comprises a sleeve 29 of "porous material on the upstream. end of which is seated or secured as desired a p ortion 433 having its substantially circular base 428 seated within the upstream end of the socket 24 upon the upstream end of sleeve 29 to which it may be suitably secured if desired. The base 428 has a sliding fit with the valve stem shank portion 3| toprovi'de guidance forthe latter and to form therewith a relatively tight fluid- 55 V on said nozzle body and said valve. stem shank the sleeve 28. Assh'ownin Fig. 10 portion 533 of thefilter bushing structure which maybe used to limit valve: stemutravel may be formed intew 'gral: with and of the same material as the porous sleeve 539 with an intervening section 528 providing for proper positioning of the filter sleeve 539 in the socket 2 4. and suitable guidance for the: valve stemshank 3i. Grooves 538 538 provide-for passage of fuel in likemanner as do grooves 38:-.3& or the structure shown in Figs.

i all; will thus be seen that the objectsset forth above are attained in an efiicient manner and since certain changes may be made inthe above construction and: dii ieren-t embodiments, of the invention could be made without: departing from the scope thereof, it isintended that all matter contained in the above description. orshown. in

the accompanying drawingslshall be interpreted as illustrative and not in a limiting sense.

.It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein. de-

scribed,and all statements of o the scope of the invention which, as a matter of language, might besaid to falltherebetween'. y. l H

Having described our inventiomwhat welclaim as new and desire to secure by Letters Patent. is: 1'. A nozzle for injecting :fuel' intocom-bustion chambers comprising, in combination, a. nozzle body :having a bore therein providinga fuel passagea valve stem in the bore having a valve near the. downstream end of the bore to. control flow of fuelland provided with a portion adjacent the valve to cooperate with the wall of the bore forgu-ided reciprocation, said valve stem having a shank portion projecting, upstream of said valve into an enlarged portion of the bore, a filter bushing structure seated in the enlarged portion of the bore with the shankportion of said valve ste'mprojecting :therethrough, said filter bushing structure including a substantially cylindrical upstream end. having portions. of the outer surface thereof set back to provide for free passage of fuel to between the filter bushing structure and the adjacent wall of the bore,

meanson said valve stem shank portion to, co-

operate with the upstream end of saidfilterybush ing fistructure for limiting travel of said ,valve stem, and spring means in the enlarged portion of the bore. cooperating with abutment means portion biasing the valve to closed position. 11

2. A nozzle for injecting fuel into combustion chambers comprising, in combination, a nozzle body including a tip member and having a passage extending'therethrough adapted to. be

connected to fuel supply, the passage beingenlarged upstream of theupstream end of said tip. member to provide a working chamber, said tip member having a bore therethrough forming a part. of the; passage and provided with a valve seatavalve' stem inthe. passage having a valve to cooperate with said seat to control flow of fuel: and provided with a shank portion project.- ing upstream. from said tip member into; the working. chamber, the bore in said tip member being enlarged upstream of the valve seat to, Pro;- vide .a socket; a filter structure seated in the socket with theshank portion: of said valve-stem projecting therethro l hg said filter structure having an end portion projectinginto' the working chamber and providing guidance for said valve stem shank portion, means on said shank portion and said filter for limiting travel of said valve stem, and spring means in the working chamber abutting the upstream end of saidtip member and biasing the valve to closed position.

3. A nozzle for injecting fuel into combustion chambers comprising, in combination, a nozzle body including a tip member and having a passage extending therethrough adapted to be connected to fuel supply, the passage being enlarged upstream of the upstream end of said tip member to provide a working chamber, said tip member having a bore therethrough forming a part of the passage and provided with a valve seat, a valve stem in the passage having a valve to cooperate with said seat to control flow of fuel and provided with a portion adjacent the valve to cooperate with the wall of the bore for guided reciprocation, said valve stem having a shank portion projecting upstream from said tip member into the working chamber, the bore in said tip member being enlarged upstream of the valve seat to provide a socket, a filter bushing structure seated in the socket with the shank portion of said valve stem projecting therethrough, said filter bushing structure having a substantially cylindrical end portion projecting into the working chamber and providing guidance for said valve stem shank portion, said bushing end portion having portions of the outer surface thereof set back to provide for free passage of fuel to between the filter bushing structure and the adjacent wall of the socket, means on said shank portion to cooperate with said end portion of said filter bushing structure for limiting travel of said valve stem, spring abutment means on saidvalve stem shank portion projecting into the working chamber, a valvebiasing helical spring between the upstream end of said tip member and spring abutment means and arranged about said substantially cylindrical end portion of said filter bushing structure with the latter serving as a guide for said spring,

said filter bushing structure having a shoulder near the upstream end of said tip member to define the cylindrical end portion, and a filter bushing travel limiting annulus interposed between said shoulder and the downstream end of said spring.

4. In a nozzle for injecting fuel into combustion chambers, the combination comprising, a tip member having a bore therein providing a, fuel passage, the bore near the downstream end of the tip member being so shaped as to provide a valve seat and enlarged upstream of the valve seat to provide a socket, a filter bushing structo limit travel of said valve stem, and spring means abutting the upstream end of said tip member and cooperating withabutment means on said shank portion biasing the valve to closed position. i

5. In a nozzle for injecting fuel into combustion chambers, the combination comprising, a tip member having a bore therein providing a fuel passage, the bore near thedownstream end of the tip member being so shaped as to provide a valve seat and enlarged upstream of the valve seat to provide a socket, a filter bushing structure seated in the socket having abutment means near the upstream end of said tip member and a portion means on said shank portion biasing the valve toclosed position, said spring being of such dimension as to cooperate with said abutment means on said filter bushing structure to retain the latter in said socket with said projecting portion received within the spring to serve as a guide.

6." In a nozzle for injecting fuel into combustion chambers, the combination comprising, a nozzle 'body having a bore therein providing 'a fuel passage, a valve stem in the bore having a valve near the downstream end of the bore to control flow of fuel, said valve stem having a shank portion projecting upstream of said valve into an enlarged portion of the bore, a filter bushing structure seated in the enlarged portion of the bore with the shank portion of said valve stem projecting therethrough, said filter bushing structure comprising a sleeve of porous fuel-fil tering material having at least a mid-section spaced from the wall of the enlarged bore portion and said valve stem providing inner and outer fuel spaces on opposite sides thereof and end means one of which has a substantially fluidsealing sliding fit with said valve stem and the other of which has a substantially fluid-sealingfit with a wall of the bore, and spring means biasing said'valve to closed position and overlying a portion of said filter bushing structure to retain the latter seated in said bore. 7," In a nozzle for injecting fuelinto combustion chambers, the combination comprising, a nozzle body having a bore therein providing a fuel passage, a valve stem in the bore having a valve near the downstream end of the bore to control flow of fueLsaid valve stem having a shank portion projecting upstream of said'valve into an enlarged portion of the bore, a filter bushing structure seated in the enlarged portion of the bore with the shank portion of said valve stem projecting therethrough, said filter bushing structure comprising a sleeve of porous fuel-filtering material having at least afmi'dsection spaced from the wall of the enlarged bore portion and said valve stem providing inner-and outer fuel spaces on opposite sidesthereof and means providing a substantially fluid-sealing sliding fit with said valves stem upstream of the'fuel spaces and a substantially fluid-sealing fit with a wall of the bore downstream of the fuelspaces with provision for passage of fuel between'said sleeve and said valve stem from the inner fuel space to said valve, and spring means,for biasing said valve to closed position and for retaining said filter bushing structure in said enlarged portion of said bore. y 'WARNER. T. TABB. I M. PURDY, 

